The results showed that 24.1 percent of the girls had one of these STDs and among girls who were sexually experienced, 37.7 percent had an STD.

HPV was the most common infection (18.3 percent), followed by chlamydia (3.9 percent).

Moreover, in the year after having their first sexual experience and with only one sex partner, 19.2 percent of the teens developed an STD, Gottlieb’s group found.

The report is published online Nov. 23 and in the December print issue of the journal Pediatrics.

To combat these problems, Gottlieb suggests teens should have early sex education:

“The vast majority of people have sex for the first time during their teenage years, so we need them to be prepared,”

In addition, Gottlieb believes that 11- and 12-year-old girls should get the HPV vaccine:

“We have an effective and safe vaccine that can prevent most of the bad consequences of HPV infection cervical cancer…

“Teen girls and young women should also have a yearly test for chlamydia. This can prevent some of the adverse consequences of chlamydia, such a pelvic inflammatory disease and infertility,”

Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, said:

“The authors make a convincing case that rates of both sexual activity and sexually transmitted infections are high in adolescent females in the U.S.”

These are the facts of epidemiology, not ideology, and should be the basis for public health policy, he said.:

“Adolescent girls need early access to comprehensive sex education, and barrier contraceptives. This will not increase sexual activity, but it will attenuate the resultant harms.”

This study also makes a strong case for routine vaccination against HPV, as it is the most common sexually transmitted infection, Katz said:

“Since HPV is often acquired so soon after the initiation of sexual activity, early vaccination is the way to go. I speak on this as the father of two young teenage daughters, both of whom have received the Gardasil vaccine,”

Another report released by the CDC last week provided more statistics, further backing the evidence already provided by previous studies.

Teen girls aged 15 to 19 accounted for the largest number (409,531) of the 1.5 million reported chlamydia and gonorrhea cases in the United States in 2008, followed by women aged 20 to 24, according to the annual federal report.

The researchers also found that black females continue to have a higher rate of STDs than any other racial or ethnic group.

Last year, there were about 1.2 million reported cases of chlamydia and nearly 337,000 reported cases of gonorrhea in the United States, according to the report.